1 Summary

The GEMS monitoring sites were established to measure key air pollutants associated with adverse effects on people’s health and well-being. The GEMS sites include some of the longest running air quality monitoring sites in New Zealand. For example, total suspended particulates (TSP) and Lead (Pb) monitoring has been undertaken at the Gavin Street, Penrose site in Auckland since 1964. The GEMS sites have provided long-term continuity in monitoring data for Auckland and Christchurch, and have recorded trends in pollution levels in two of New Zealand’s largest cities.

There is currently one monitoring site in Auckland which is representative of vehicle and industrial emissions (Gavin Street, Penrose). The Greers Road, Burnside site in Christchurch is located within a residential area and represents emissions from domestic properties.

Air pollutants arise from a number of different sources. The pollutants monitored at the GEMS sites include:

• particulate matter (PM₁₀) – principally from domestic heating, vehicle emissions and industrial processes (as well as natural processes such as soil erosion and sea spray)

• nitrogen oxides (NO and NO₂) – mostly from motor vehicle emissions

• sulfur dioxide (SO₂) – produced from the burning of fossil fuels, particularly coal and oil

• carbon monoxide (CO) – a product of incomplete combustion of carbon containing fuels, especially from motor vehicles

• total suspended particulates (TSP) – particles sufficiently small enough to be inhaled but due to its size are readily filtered out in the nasal cavity

• volatile organic compounds (VOCs) – organic chemicals, such as hydrocarbons, that are closely tied to vehicle emissions and many industrial processes

• lead (Pb) – was a petrol additive but since the significant reduction of lead in petrol from 1996, levels have declined in New Zealand.

Ambient air quality standards for CO, NO₂, SO₂, PM₁₀ and ozone were promulgated in October 2004. The purpose of these standards is to provide a guaranteed level of protection for the health of all New Zealanders.¹ Guideline levels for pollutants (and averaging periods) not covered by the standards still apply.

All air pollutants monitored at all the sites (with the exception of Greers Road, Burnside) were below the national environmental standards (NES) for air quality as well as the ambient air quality guidelines (AAQG) for all averaging periods. The Greers Road, Burnside site had 11 exceedences of the 24-hour standard for PM₁₀, mainly during the colder months from May to August 2008. These exceedences were most likely due to home heating emissions. The NES for air quality allows for one exceedence of the PM₁₀ 24-hour threshold per year before the standard is breached.